Wei N, Deng X W
Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA.
Photochem Photobiol. 1998 Aug;68(2):237-41. doi: 10.1562/0031-8655(1998)068<0237:capotm>2.3.co;2.
The COP9 complex has been identified as a repressor of photomorphogenesis in Arabidopsis. Here we demonstrate that the COP9 complex is also present in mammals. Specific antibodies were generated against human counterparts of the Arabidopsis COP9 and COP11, the two known subunits of plant COP9 complex. Using these antibodies, we showed that indeed mammalian COP9 and COP11, also known as GPS1, could be coimmuno-precipitated using either of the two specific antibodies, definitively confirming that they are physically part of the same complex. Further, the mammalian COP9 and COP11/GPS1 were cofractionated in the same large molecular weight fractions of about 500 kDa and were absent from the monomeric fractions. The mammalian COP9 complex was present in all organs examined but abundances vary. Indirect immunofluorescence studies suggested that the mammalian COP9 complex is largely nuclear localized. Both conventional biochemical and affinity purifications of the COP9 complex from pig spleen indicated that the mammalian COP9 complex consists of eight distinct subunits. These findings indicate that mammals also have a COP9 complex with conserved molecular composition and biochemical and cellular properties similar to the higher plant counterpart.
COP9复合体已被确定为拟南芥中光形态建成的抑制因子。在此我们证明，COP9复合体在哺乳动物中也存在。针对植物COP9复合体的两个已知亚基——拟南芥COP9和COP11的人类对应物，制备了特异性抗体。使用这些抗体，我们表明，实际上哺乳动物的COP9和COP11（也称为GPS1），可以用这两种特异性抗体中的任何一种进行共免疫沉淀，从而明确证实它们是同一复合体的物理组成部分。此外，哺乳动物的COP9和COP11/GPS1在约500 kDa的相同大分子量组分中被共分级分离，而在单体组分中不存在。哺乳动物的COP9复合体存在于所有检测的器官中，但丰度有所不同。间接免疫荧光研究表明，哺乳动物的COP9复合体主要定位于细胞核。从猪脾脏对COP9复合体进行的传统生化和亲和纯化均表明，哺乳动物的COP9复合体由八个不同的亚基组成。这些发现表明，哺乳动物也有一个COP9复合体，其分子组成、生化和细胞特性与高等植物的对应物相似且保守。
